This invention relates to an improved air driven pump apparatus and method for pumping a product such as a beverage syrup used in carbonated beverages. More particularly, the present invention relates to a pumping apparatus and method for providing a constant, low flow rate without mixing air or other impurities into the product being pumped.
As is well known, a variety of beverages are marketed to retail consumers by dispensing systems which simultaneously deliver a metered quantity of flavored syrup with a proportional quantity of carbonated water or the like. For sanitation and economic concerns, the beverage industry typically supplies these flavored syrups in collapsible bag-in-box containers which are adapted to be connected to suitable prior art dispensing systems.
The majority of the prior art dispensing systems have utilized low flow rate pumps for drawing the syrup from the bag container and supplying a metered quantity of the syrup to a mixing nozzle. The use of such low flow rate pumps has been advantageous for system reliability concerns. The syrups are normally concentrated and are mixed with relatively large volumes of carbonated water which means that undesired small variations in the quantity of syrup supplied will produce wide variations in the taste and quality of the final mixed product. Although prior art dispensing systems have generally proven suitable for their intended purposes, they possess inherent deficiencies which have detracted from their overall effectiveness and use in the trade. Fore most of these deficiencies has been the inability of the prior art dispensing systems to eliminate the ingestion of air into the pump and then mixing the air with the product being dispensed. Inducing air into the dispensing system typically occurs when the pump encounters a syrup depletion condition within the syrup bag container. As will be recognized, air ingestion into the dispensing system necessarily introduces inaccuracy in the quantity of dispensed syrup and thus adversely affects the quality of the resultant beverage. In extreme cases, air ingestion causes overheating the permanent damage to the pump of the dispensing system. Although these air ingestion deficiencies have been recognized to a limited extent in the air, the solutions to date have typically been ineffective or have used devices so complicated that they are excessively expensive and unreliable.
Thus, there exists a substantial need in the art for a reliable, relatively inexpensive apparatus and method for dispensing syrup at a low flow rate suitable for properly dispensing the syrup through a nozzle and which prevents air ingestion into the dispensing system.